Recently, Google changed their accounts infrastructure so that Google Apps accounts behave more like normal Google accounts. You’d think this would be a good thing, but it’s had a very negative unintended consequence.
Previously, you could associate multiple email addresses, including Google Apps email addresses, with a single Google Profile. This has been extremely useful, especially for using a product like Google Groups.
Their recent infrastructure change reversed all of this. Specifically, I use email@example.com to log into my Google services, but use firstname.lastname@example.org and other email addresses with my Google Groups. Because the Google Apps email addresses can no longer be associated with my primary Gmail account, I can no longer participant in the myriad of Google Groups I’m a part of. Furthermore, I have no idea where else this problem is going to manifest itself.
Google won’t ever get social because they’ve just fundamentally broken the concept of one login for multiple identities and contexts. As strongly as I am against it, this is what Twitter and Facebook are doing right.